Simulation Study On The Influence Of The Late Effect Of HEMP On The Traction Power Supply System

The late effect of high-altitude nuclear electromagnetic pulse（E₃）will cause dramatic changes in the earth’s magnetic field and form a earth surface potential（ESP）.As the excitation source,ESP forms a loop with the long-distance conductor and the earth in the traction power supply system to generate geomagnetic induced current（GIC）.GIC can cause the DC bias of the transformer in the traction power supply system,which will affect the safety of railway traffic.At present,the domestic research on the coupling effect of E₃ and railway traction power supply system is still blank.This research can provide support for my country’s railway planning and design,equipment selection,etc.In this paper,based on the actual subject of the Key Laboratory of Electromagnetic Environment Effects and Information Processing of Hebei Province,this paper studies the E₃ coupling effect of the railway traction power supply system.The main work is as follows:（1）Research on GIC algorithm of traction power supply system under E₃.Based on the plane wave theory,the layered earth conductance model and the circuit model of the traction power supply system,the GIC algorithm of the traction power supply system under the action of E₃ is proposed,and the direct power supply method with return line and the AT power supply method are used as an example of railway traction power supply system for the first time.Calculated the system GIC situation.The results show that the GIC in the traction power supply system under different power supply modes is far greater than the withstand value of the transformer and other equipment in the system,which lays the foundation for further research on the effect of the traction power supply system under the action of E₃.（2）Research on uncertainty of GIC of traction power supply system under E₃.In order to consider the uncertainty in the calculation of GIC,the parameters of the traction power supply system,the angle between the direction of the ESP and the direction of the railway,and the distance of the electric locomotive under the independent and joint influence of the traction power supply system GIC are calculated based on the Monte Carlo simulation method.Probability distribution and confidence interval,and based on the Sobol sensitivity analysis method,the sensitivity of the above uncertain parameters in the GIC calculation of the traction power supply system is analyzed.（3）Simulation research on the influence of E₃ on the transformer in the traction power supply system.In order to study the effects of GIC on the equipment in the traction power supply system under the action of E₃,the no-load test model of the transformer was built based on the research of the first two chapters based on PSCAD software,and the influence of GIC on the excitation current and harmonics of the transformer under the action of E₃ was studied.It shows that E₃ will cause serious saturation of the transformer core in the traction power supply system,resulting in serious distortion of the transformer excitation current and increase of harmonics,and endangering the safety of railway traffic.